• 해양환경안전학회지
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• 제29권3호
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• pp.281-287
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• 2023

Establishing a ship's passage plan is an essential step before it starts to sail. The research related to the automatic generation of ship passage plans is attracting attention because of the development of maritime autonomous surface ships. In coastal water navigation, the land, islands, and navigation rules need to be considered. From the path planning algorithm's perspective, a ship's passage planning is a global path-planning problem. Because conventional global path-planning methods such as Dijkstra and A^* are time-consuming owing to the processes such as environmental modeling, it is difficult to modify a ship's passage plan during a voyage. Therefore, the D^* algorithm was used to address these problems. The starting point was near Busan New Port, and the destination was Ulsan Port. The navigable area was designated based on a combination of the ship trajectory data and grid in the target area. The initial path plan generated using the D^* algorithm was analyzed with 33 waypoints and a total distance of 113.946 km. The final path plan was simplified using the Douglas-Peucker algorithm. It was analyzed with a total distance of 110.156 km and 10 waypoints. This is approximately 3.05% less than the total distance of the initial passage plan of the ship. This study demonstrated the feasibility of automatically generating a path plan in coastal navigation for maritime autonomous surface ships using the D^* algorithm. Using the shortest distance-based path planning algorithm, the ship's fuel consumption and sailing time can be minimized.

• 한국조경학회지
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• 제26권2호
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• pp.293-307
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• 1998

This study has been divided into two parts, 1) literature review and 2) a case study. Based on literature review and case studies found in Korea and abroad, this study aimed at classifying wildlife passages and establishing their development procedures in order to establish a theoretical ground for the development of wildlife passage as a way to link habitats that have been fragmented by the construction of roads and other developments. The results of the literature review are as follows : 1) Impact of road construction on surrounding ecological environment is found in various aspects. Along with damage of habitats as direct impact, decrease of biodiversity and simplification of species due to limited breeding and movement are cited as possible indirect impact. 2) In order to lessen the impact generated from fragmented habitats, various types of wildlife passage are being developed in Europe and are showing positive results. 3) In Korea, interests on animal passages have been rising recently. The ministry of Environment and local authorities are establishing development plans for the passages. However, practical materials on the usefulness of adoped methods are not available.4) In order to create an effective wildlife passage, decisions have to be made first on basic factors of planning and designing such as ecosystem rehabilitation methods and surveys on wildlife movement routes and habitat environment. Based on this, in a planning and designing stage, the location and type of a passage, size and measures to attract animals and prevent a collision need to be finalized. This should be followed by a series of process of maintenance, management and monitoring after the development. Based on the results of a theoretical study to develop an wildlife passage, Part 2 of this study deals with the results of an experiment through a specific planning and design that includes a process of ecological surveys, site selection, type selection, ecosystem infrastructure, planting design and construction details on an actual study area and presents them as a model project.

• 대한건축학회논문집:계획계
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• 제34권12호
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• pp.95-102
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• 2018

The purpose of this study is to investigate the causes of conflict that arise from public pedestrian passages installed in apartment complexes through a survey of residents' perceptions and to investigate the effects on the satisfaction with and necessity of the public pedestrian passage. This has significance as a preliminary research into determining solutions to conflict related to public pedestrian passages that are open spaces, accessible 24 hours a day to pedestrians including people who live outside of the apartment complex. The result of the residents' perception survey showed that there is conflict due to the public pedestrian passage. The main problem was the noise-related variables. While management and safety variables were also perceived as problems, privacy and ownership infringement variables were not. These problems were reduced to four factors through a factor analysis: unfavorable incidents, environment management, ownership infringement, and safety crimes. Analyzing the effects of the above factors on the satisfaction with the apartment complex, satisfaction with the public pedestrian passage and the necessity of the public pedestrian passage, demonstrated that the unfavorable incidents factor influenced all the variables. The safety crimes factor, which is an extended concept of the unfavorable incidents, affected both the satisfaction and necessity of the public pedestrian passage. The ownership infringement factor was found to affect the satisfaction of the public pedestrian passage only, and the environment management factor did not affect all the variables. In planning and managing public pedestrian passages, avoiding incidents and crimes should be considered as a priority to increase the satisfaction of residents and solve conflicts.

• Asian-Australasian Journal of Animal Sciences
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• 제26권4호
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• pp.588-595
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• 2013

Mesenchymal stem cells (MSCs) are often known to have a therapeutic potential in the cell-mediated repair for fatal or incurable diseases. In this study, canine umbilical cord MSCs (cUC-MSCs) were isolated from umbilical cord matrix (n = 3) and subjected to proliferative culture for 5 consecutive passages. The cells at each passage were characterized for multipotent MSC properties such as proliferation kinetics, expression patterns of MSC surface markers and self-renewal associated markers, and chondrogenic differentiation. In results, the proliferation of the cells as determined by the cumulative population doubling level was observed at its peak on passage 3 and stopped after passage 5, whereas cell doubling time dramatically increased after passage 4. Expression of MSC surface markers (CD44, CD54, CD61, CD80, CD90 and Flk-1), molecule (HMGA2) and pluripotent markers (sox2, nanog) associated with self-renewal was negatively correlated with the number of passages. However, MSC surface marker (CD105) and pluripotent marker (Oct3/4) decreased with increasing the number of subpassage. cUC-MSCs at passage 1 to 5 underwent chondrogenesis under specific culture conditions, but percentage of chondrogenic differentiation decreased with increasing the number of subpassage. Collectively, the present study suggested that sequential subpassage could affect multipotent properties of cUC-MSCs and needs to be addressed before clinical applications.

• 대한건축학회논문집:계획계
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• 제34권6호
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• pp.135-142
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• 2018

A public pedestrian passage induces traffic into the apartment complex, and therefore, it requires the application of Crime Prevention Through Environmental Design(CPTED). This paper aims to analyze the conditions and to suggest the improvements of public pedestrian passages in apartment complexes, applying a 3-D approach from CPTED aspect. The first aspect is "Designation": 1)The linkage between the public pedestrian passages is weak, and their designated purpose becomes unclear. 2)When the designated purpose is not considered for each complex, the closure rate is high. 3)The closure rate of the "Through type" is high. It suggests that the pedestrian network should be built and vitalized at the local urban level. The second aspect is "Definition." The public pedestrian passage lacks a social, cultural, and legal definition and only has a passive physical definition. It suggests that a legal definition and specialized guildline be prepared. The third aspect is "Design": 1)Insufficient territoriality exists between the public pedestrian passage and the inside of the complex. Territoriality should be reinforced between the public pedestrian passage and the rest of the internal territory. 2)The landscaping adjacent to the public pedestrian passage lacks deliberation. Since this is where safety and privacy collide, detailed design and maintenance of the landscaping is required. 3)It lacks systematical crime prevention facilities and should compensate accordingly.

• 국토계획
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• 제53권7호
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• pp.5-22
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• 2018

While the competitiveness of small and medium sized cities has become important for balanced development at the national scale, they have experienced continuous decline in population and employment, particularly those in non-capital regions. In addition, some of small and medium sized cities have been classified into shrinking cities that have declined due to their long-term structural reasons. To address these issues, a regional approach, by which a hub city and its surrounding small and medium sized cities can collaborate has been suggested. Given this background, the purpose of this study is to identify and delineate hub cities and their impact areas by using travel data as a functional network index. This study uses a centrality index to identify the hub cities of small and medium sized cities and Markov-chain model and cluster analysis to delineate regional boundaries. The mean first passage time (MFPT) generated from the Markov-chain model can be interpreted as functional distance of each region. The study suggests a methodological approach delineating the boundaries of regions incorporating functional relationships of hub cities and their impact areas, and provides 59 hub cities and their impact areas. The results also provide policy implications for regional spatial planning that addresses appropriate planning boundaries of regions for enhancing the economic competitiveness of small and medium sized cities and ensuring services for shrinking cities.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2023년도 춘계학술대회
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• pp.160-161
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• 2023

현재 선박의 항해계획은 항해사의 지식과 경험적인 방법에 의존하고 있다. 그러나 최근에는 선박 자율운항기술이 발전됨에 따라, 항해계획의 자동화 기술도 여러 가지 방법으로 연구되고 있다. 본 연구에서는 강화학습 기법 중 하나인 Q-러닝을 기반으로 선박 최적 항해 경로를 생성하고자 한다. 강화학습은 다양한 상황에 대한 경험을 학습하고, 이를 기반으로 최적의 결정을 내리는 방식으로 적용된다.

• International Journal of Internet, Broadcasting and Communication
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• 제16권2호
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• pp.218-226
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• 2024

According to the actual situation of a university, the emergency evacuation simulation is modeled based on the physical sign, evacuation speed and personnel ratio using the pathfinder software.The experimental construction export utilization rate is compared with the preliminary simulation scenario. The simulation results show that the utilization rate of evacuation stairs and evacuation exits is significantly improved.The optimized solution can provide the most effective evacuation passage, and the research results can provide the basis for the rational planning and management of evacuation passage in university experiment building.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권3호
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• pp.203-209
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• 2010

This paper presents a hierarchical fuzzy motion planner for humanoid robots in 3D uneven environments. First, we define both motion primitives and locomotion primitives of humanoid robots. A high-level planner finds a global path from a global navigation map that is generated based on a combination of 2.5 dimensional maps of the workspace. We use a passage map, an obstacle map and a gradient map of obstacles to distinguish obstacles. A mid-level planner creates subgoals that help the robot efficiently cope with various obstacles using only a small set of locomotion primitives that are useful for stable navigation of the robot. We use a local obstacle map to find the subgoals along the global path. A low-level planner searches for an optimal sequence of locomotion primitives between subgoals by using fuzzy motion planning. We verify our approach on a virtual humanoid robot in a simulated environment. Simulation results show a reduction in planning time and the feasibility of the proposed method.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2002년도 추계학술발표대회
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• pp.197-201
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• 2002

The purpose of this study is to provide the information of street planning for revitalization oft the community in urban detached housing area. This study was accomplished by observations and actual survey, and suggested several street planning methods; exclusion of the passing through car and control of the resident's car by one-way passage, protection of the parking area to inside individual lot by the ‘Break down Fence’ campaign in Daegu, and provide the common space for social contact and community According to this program, the public street space cant be changed into the semi-private space and the semi-public space as common territory.